NEMI Method Summary

Method Summary Information

Method Number: 4500-NO3- E Media: WATER
Revision: Standard Methods Online
Method Source: Standard Methods
Subcategory: INORGANIC Analytes in this method
Official Name: Nitrate in Water by Colorimetry and Cadmium Reduction
Descriptive Name Nitrate in Water After Cadmium Reduction
Source Info: Standard Methods Online is jointly produced by the American Public Health Association (APHA), the American Water Works Association (AWWA), and the Water Environment Federation (WEF).
These organizations may be contacted by phone for more information on Standard Methods Online:
APHA: (301) 893-1894
AWWA: (800) 926-7337, (1-303-794-7711, outside U.S. / Canada)
WEF: (800) 666-0206 (1-703-684-2452 outside U.S. / Canada)
Citation: Standard Methods Online
 
Brief Method
Summary:
 Nitrate is reduced almost quantitatively to nitrite in the presence of Cd. The nitrite thus produced is determined by diazotizing with sulfanilamide and coupling with N-(1-napthyl)-ethylenediamine dihydrochloride to form a highly colored azo dye that is measured colorimetrically.
Scope And
Application:
 This method allows for determination nitrate and nitrite in water. This method will determine between 0.01 and 1 mg NO3-N/L.
Applicable
Conc Range:
 0.01 - 1.0mg/L
Interferences: (1) Suspended matter restricts sample flow. (2) Metals (e.g., iron, copper) lower reduction efficiency. (3) Oil & Grease which coats the column. (4) Residual chlorine which oxidizes the reduction column. (5) Colored samples that absorb at ~540 nm.
QC Requirements: None
Sample Handling: Collect 100 mL sample in a plastic or glass container. When storing sample for > 1 day, preserve with 2 mL concentrated H2SO4/L. Refrigerate at 4 C. Individual species NO3- and NO2- cannot be determined from preserved samples. Analyze within 48 hours.
Max Holding Time:
 48 hours
 
Relative Cost: Less than $50
URL to obtain ordering information for this method:
http://www.standardmethods.org/
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